Problem: $ { \left[\begin{array}{rrr}{-1} & {0} & {-2} \\ {3} & {1} & {1}\end{array}\right]+\left[\begin{array}{rrr}{-2} & {4} & {3} \\ {-1} & {1} & {1}\end{array}\right] = {?} } $
Explanation: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-1}+{-2} & {0}+{4} & {-2}+{3} \\ {3}+{-1} & {1}+{1} & {1}+{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-3} & {4} & {1} \\ {2} & {2} & {2}\end{array}\right]}$